L3: Bones, ligaments and joints of the forearm (incl. elbow) Flashcards
humerus
long bone of arm
articulates with scapula proximally - GH joint
articulates with bones of the forearm distally - ulna medially + radius laterally
wrist drop
because wrist extensors stop working without input from the radial nerve
ulnar nerve
runs postero-inferior to the medial epicondyle
hitting your funny bone is in fact a compressive injury to the ulnar nerve
golfers elbow
medial epicondyle: proximal attachment for muscles that flex the wrist. used to flex wrist in a golf swing
tennis elbow
lateral epicondyle: proximal attachment for muscles that extend the wrist. used in backhand strokes in tennis
ulna and radius
bones of forearm
anatomical position: ulna medial + radius lateral
articulate with the humerus proximally - elbow joint
articulate with the carpals distally - wrist
ulna - proximal features
large trochlear notch
large olecranon process
coronoid process
radial notch
ulnar tuberosity
ulna - shaft
interosseous ridge descends along the lateral shaft
ulna - distal features
head of ulna
styloid process
radius - proximal features
head of radius
neck
radial tuberosity
radius - shaft
interosseous ridge
radius - distal features
tubercles and groves on posterior surface
styloid process ( larger than ulna)
radius role
moves around the ulna during supination and pronation of forearm
interosseous membrane
aka interosseous ligament
fibrous joint [syndesmosis]
sheath of fibrous connective tissue
between interosseous ridges of ulna and radius
prevents separation, yet allows for pronation and supination of forearm
movements of the elbow
extension
flexion
movements of the forearm
supination/ pronation
these movements occur at the:
proximal radioulnar join
distal radioulnar joint
elbow joint - fibrous capsule
classified as synovial hinge joint
-joint capsule lined by synovium
-synovial fluid inside the capsule
-articular surfaces of bones lined by hyaline cartilage
capsule attached to the articular margins of joint
elbow joint
is loose anteriorly / posteriorly to allow for a full range of flexion / extension
in hyperextension injuries, the anterior joint capsule can be stretched / ruptured
elbow joint - ulnar collateral ligaments
reinforces the joint medially
superior band
inferior band
posterior band
elbow joint - radial collateral ligament
reinforces the joint laterally
base is attached to the annular ligament and ulna
apex attaches to the lateral epicondyle
elbow dislocation
very stable hinge synovial joint
mechanism of injury
posterior dislocation
- usually FOOSH
anterior dislocation
- rare
- high energy incidents
radioulnar joints - 3
proximal radioulnar joint
intermediate radioulnar joint
distal radioulnar joint
proximal radioulnar joint
radial head in radial notch of ulna
synovial pivot joint
in same capsule as elbow joint
intermediate radioulnar joint
fibrous joint: syndesmosis
formed by interosseous membrane
distal radioulnar joint
ulnar head in ulnar notch of radius
synovial pivot joint
the annular ligament
position:
anterior margin of radial notch of ulna
around neck of radius
to posterior margin of radial notch of ulna
holds the radial head in the radial notch of the ulna
nursemaid’s elbow
the head of the radius tends to be proportionately smaller in children under 5 years
if enough force is applied in the distal direction, it can slip under the annular ligament and become dislocated
